Financing Receivables (Allowance for Loan Losses) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020		Jun. 30, 2019	Jan. 01, 2020	Dec. 31, 2019
Commercial Loan [Member]
Rollforward of the allowance for loan losses
Beginning balance				$ 51	[1]	$ 49
Provision for Loan, Lease, and Other Losses		$ 13				2
Write-offs		1	$ (1)
Recoveries		0
Ending balance		65	50	65		50
Accrued interest		13		13				$ 14
Commercial Loan [Member] | Accounting Standards Update 2016-13 [Member]
Rollforward of the allowance for loan losses
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets							$ 2
Consumer Loan [Member]
Rollforward of the allowance for loan losses
Beginning balance	[1]			0
Provision for Loan, Lease, and Other Losses		3
Write-offs		(2)
Recoveries		0
Ending balance		4		4
Consumer Loan [Member] | Accounting Standards Update 2016-13 [Member]
Rollforward of the allowance for loan losses
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets							3
Total Segment [Member]
Rollforward of the allowance for loan losses
Beginning balance	[1]			51
Provision for Loan, Lease, and Other Losses		16
Write-offs		(3)
Recoveries		0
Ending balance		69		69
Total Segment [Member] | Accounting Standards Update 2016-13 [Member]
Rollforward of the allowance for loan losses
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets							$ 5
Syndicated loans [Member]
Rollforward of the allowance for loan losses
Loans purchased		13	41	69		74
Loans sold		0	$ 14	7		$ 27
Residential Mortgage [Member]
Rollforward of the allowance for loan losses
Loans purchased		$ 22		$ 22

[1] Prior to January 1, 2020, the allowance for credit losses was based on an incurred loss model that did not require estimating expected credit losses over the expected life of the asset.